31results about How to "Control supersaturation" patented technology

The invention relates to a method for preparing nano catalytic composite materials by utilizing an integrating process of an ultrasonic-film-anti-solvent method, comprising the following steps of: (1) the ammonium porchlorate saturated solution preparation process: dissolving ammonium porchlorate into a proper solvent to prepare the ammonium porchlorate saturated solution at certain temperature; (2) the dispersing process of a nano catalyst: uniformly dispersing the nano catalyst into an anti-solvent under ultrasonic action; (3) the preparing process: adding the AP (ammonium porchlorate) saturated solution to a nonsolvent through a film tube under certain pressure, wherein after the anti-solvent carries out desolvation on the solvent, the ammonium porchlorate is separated out and covers on the surfaces of uniformly-dispersed nano particles to form the nano catalytic composite materials; (4) filtering and drying processes: firstly carrying out solid-liquid separation on nano composite particles; and (5) the drying process: drying separated materials at 50-150 DEG C to obtain the nano catalytic composite materials. The nano catalytic composite materials prepared by the method have stable structure, uniform nano catalyst dispersion and controllable particle diameter and appearance.

The invention provides a new technology of applying the double-effect forced circulation concentration method in the production of ammonium phosphate, which comprises the steps of carrying out double-effect forced circulation flash distillation on phosphoric acid slurry, removing excess moisture in the phosphoric acid slurry and reacting with neutralizing slurry so as to generate intermediate slurry, enabling the intermediate slurry to be reacted with ammonia gas to generate a product, carrying out one-effect forced circulation flash distillation on the product slurry, further preparing qualified monoammonium phosphate slurry, drying and granulating by a fluid bed, packaging and weighing. Heat quantity generated by neutralization reaction is taken as a one-effect flash distillation heat source, and the excess heat in the one-effect flash distillation process is taken as a double-effect flash distillation heat source. With the adoption of the new technology, the heating steps in the production process are reduced, the quantity and height of devices used are decreased, heat energy is used reasonably, and energy consumption is reduced. The temperature difference between an inlet and an outlet of a heater is only 1-3 DEG C, degree of supersaturation can be controlled effectively, and scaling of the pipe wall of a heat exchanger is reduced. The forced circulation can enable the circulation speed of liquid phase to improve greatly, wash the wall pipe, and play an important role in reducing the scaling. The cycle of operation of a device is increased greatly, productive capacity is improved obviously, and the production cost is reduced effectively.

The invention relates to a method for preparing nanometer MgO whiskers at the low temperature and the method is that magnesium powders and amorphous boron powders are mixed according to atomic ratio of MG:B being equal to 1 to 1.5:2 and the mixture is grinded for 30 to 120 minutes for thorough mixing, and after the mixed powders are made into a lump sinter under the pressure of 5 to 10 kg / cm<3> bya press machine, the lump sinter is put into a crucible which is put into a heating zone of an evacuated tubular furnace. The evacuated tubular furnace is sealed, vacuumized to 1 to 10 Pa and filledwith argon the oxygen content of which is 2 percent to 5 percent and the flow rate of the mixed gas is 5 to 20 lit. per minute to heat the sample up to 650 to 750 DEG C at the heating rate of 5 to 20K per minute, and the sample is decreased to the room temperature at the same heating rate after the temperature is kept for 0 to 120 minutes. The surface of the sample forms nanometer MgO whiskers with various appearances and sizes. When reaching 650 DEG C, magnesium evaporates and reacts with the little filled oxygen to produce MgO vapour, and under the lower over-saturation state, MgO whiskersare deposited on a substrate. The method for preparing MgO whiskers needs temperature much lower than the previous and greatly increases the practicality of preparing MgO whiskers.

The invention provides a device for accelerating desorption of PM2.5 (Particulate Matter 2.5) fine particulate matters by utilizing vapor phase change and condensation. The device comprises a group of desorption towers which are sequentially connected, wherein flue gas inlets are formed in the bottoms of the desorption towers, flue gas outlets are formed in the tops of the desorption towers, and stream inlets are formed in the side walls of the desorption towers. According to the device, the structure is simple, and the cost is low; and by arranging a group of the desorption towers which are sequentially connected, the supersaturation degrees of the desorption towers are effectively controlled, so that the PM2.5 fine particulate matters in the gas are desorbed step by step; and the efficiency is high, and the energy consumption is low.

The invention discloses a long-term stabilization treatment method for arsenic in arsenic-containing waste liquid, which comprises the following steps: (1) mixing arsenic-containing waste liquid with ferrous sulfate solution, adjusting the pH, temperature and oxidation-reduction potential of the mixed liquid, and arsenic-precipitated products Washing and drying to obtain crystalline scorodite; (2) high-speed stirring and granulation of crystalline scorodite and silicon-acrylic emulsion to form primary coated particles with scorodite as the core and silicon-acrylic emulsion as the shell. Press molding in a mold and dry to obtain scorodite core-shell-coated solidified body body; (3) Soak the solidified body body in step (2) in silicon-acrylic emulsion, take it out and dry it, and finally obtain arsenic-containing minerals cured body. The arsenic-containing solidified body obtained by the method has high density, high arsenic content, low arsenic leaching toxicity and good long-term stability.

The invention discloses a preparation process and device system for continuous cooling and crystallization of ethyl carbazole, which solves the problem that floating crystals are prone to appear in the process of preparing ethyl carbazole in the traditional process, resulting in high moisture content of crystals and easy preparation of powdery crystals. question. The invention includes a preparation process of continuous cooling and recrystallization of ethyl carbazole. The ethyl carbazole crude product and ethanol solvent are mixed according to the mass ratio, and after heating and dissolving, the temperature is lowered for the first time, and the solution temperature is reduced to a supercooling degree of 1 ℃~4℃, add ethyl carbazole seed crystals with a particle size of 0.05mm~0.1mm, keep warm, and then lower the temperature to the crystallization temperature for the second time to obtain the mother liquor of continuous crystallization. Ultrasonic treatment is carried out on the pre-configured raw material solution, and the crystallization time is controlled, followed by centrifugation, washing and drying to obtain ethyl carbazole granule products; the above-mentioned preparation process is used to provide the device system. The invention has the advantages of being able to continuously cool and recrystallize to prepare short rod-shaped ethyl carbazole, and at the same time completely avoid the generation of floating crystals.

The invention discloses a method for precipitating and separating rare earths in a calcium-containing rare earth solution. Specifically, the concentration of rare earths is 0.1-1.5 mol / L, the concentration of calcium ions is 0.1-1.0 mol / L, and the molar ratio of rare earths to calcium is 0.7≤ The calcium-containing rare earth solution with X≤8.0 is the object, and the rare earth in the calcium-containing rare earth solution is precipitated by bicarbonate, and the conditions such as temperature, pH, and feeding speed during the precipitation process are adjusted and controlled according to the molar ratio of rare earth and calcium in the solution, so that Adjust the concentration of bicarbonate in the solution to control the stability of calcium bicarbonate and the supersaturation of rare earth carbonate, so that rare earth ions precipitate to form crystalline rare earth carbonate, and calcium ions form soluble calcium bicarbonate, so as to realize calcium-containing rare earth solution High-efficiency separation of medium rare earth and calcium, and rare earth oxides with a purity greater than 98%.

The invention discloses a continuous crystallization manufacturing process of medicinal glauber salt, which comprises the following step: removing mechanical impurities of original aqueous glauber salt with a certain concentration transported underground by a three-level pipeline filer under the monitoring of a DCS automatic monitoring system and the adjustment and control of an AK liquid balanceflowmeter; refining and purifying by an eight-level ion exchanger to obtain refined aqueous glauber salt with a very low impurity content; introducing into a continuous crystallization process system; carrying out continuous solid-liquid separation by a multistage tandem centrifuge; and finally packing by an automatic packing system to obtain the glauber salt conforming to the pharmaceutical grade of Chinese Pharmacopoeia.

The invention relates to the preparation field of chemical industrial materials, and particularly relates to a preparation method of a fibrous alkali magnesium sulfate whisker. The preparation method of the fibrous alkali magnesium sulfate whisker comprises the following steps: (1) preparing a magnesium sulfate solution by using MgSO4.7H2O, stirring and adding NaOH granular caustic soda, aging for 2-24 hours at the temperature of 25 to 100 DEG C to obtain a slurry; (2) transferring the slurry obtained in the step (1) into a hydrothermal reactor, wherein the filling degree is 50-80 percent, adding 0.5-5 percent of seed crystal according to the mass of the NaOH granular caustic soda, uniformly stirring, and reacting the slurry for 2-12 hours at the temperature of 130-180 DEG C; (3) cooling after finishing the reaction of the step (2), filtering, washing and drying a obtained white turbid liquid to obtain the fibrous alkali magnesium sulfate whisker. According to the preparation method, the seed crystal is added into the reaction slurry, alkali magnesium sulfate is easily subjected to nucleus formation growth, and the preparation concentration of the reaction slurry can be relatively high; the whisker nucleation time is reduced, and the whisker growth time also can be shortened.

The invention specifically relates to a method for prolonging the shelf life of thiourea dioxide products. The technical plan is: under the conditions of 0~30°C and 300~600r / min rotating speed, add crystal seeds to the saturated aqueous solution of thiourea dioxide, grow the crystals, and obtain a suspended crystal slurry; then add and dissolve the suspended crystal slurry Analyzing agent, elution crystallization, filtration and drying to obtain thiourea dioxide crystals, the crystal product meets HG? High stability requirements in the 3258-2010-T industrial thiourea dioxide standard, and its thermal stability ≥ 60min. The thiourea dioxide crystal product produced by the invention has the advantages of concentrated particle size distribution, crystalline luster on the surface, high purity, good thermal stability, etc., can effectively improve the quality of the thiourea dioxide product, improve the safety performance of its transportation and storage, and prolong the shelf life of its product.

The invention relates to the field of a technology for preparing tripotassium phosphate from wet-process phosphoric acid, especially relates to a method for preparing tripotassium phosphate from wet-process phosphoric acid. The method comprises the following steps: a content of sulfate radical in the wet-process phosphoric acid is analyzed, and rock phosphate is added, so that sulfate radical, iron ion and aluminium ion and other cations as well as fluorine ion, silicon ion and other anions form precipitation; ammonia gas or ammoniacal liquor is added, pH value is adjusted to 3-7, so that a solution of ammonium phosphate is formed, after filtering, the formed precipitation is left in the residue liquid by filtering, so that the wet-process phosphoric acid is purified, and the purity of the tripotassium phosphate produced by subsequent production is ensured. After a reaction between an ammonium phosphate slurry and potassium hydroxide or potassium bicarbonate or potash is carried out, an evaporative crystallization is carried out at a negative pressure of 0-0.01MPa, so that the quality of the tripotassium phosphate crystal is good, the purity is high, the consumption of potassium ions is reduced, the production cost is reduced, and resource waste is avoided.